I believe if it is in the form of an app from iTunes or the Android market that it would be the Chanoller revision. I’d go with either the Verbum app or Laudate (both are free, at least on iTunes). If you split-screen the Verbum app and also load the Haydock commentary on the bottom, you get a poor man’s Haydock Bible. If it’s an e-book, you’d have to check out the sample pages and compare it with an online Douay like at Veritas Bible.

I’m not aware of any digital copy of the Confraternity NT online. It would be really cool if there was.

Also, on the aforementioned ‘original Douay-Rheims’ on Amazon, I remember reading somewhere this one is being put out by a Protestant group and doesn’t include all the Catholic books. I don’t recall where I read that, so take this info with a grain of salt. There is a site out there that has the non-Chanoller DR online, but I don’t know the address.

But–for a student of Catholic doctrine, or someone just trying to faithfully study
the Holy Scriptures, are the Challoner and Confraternity editions
going to lead one astray?

I have a 1948 edition of the Confraternity D-R and love the elegance, clarity and
richness of the language. I have been using it for devotional reading.

I would go ahead and use it. The Chanoller is available from several Catholic publishers. The Confraternity NT is available from Sceptre. Both I feel are very reliable, and I haven’t heard anyone complain of problematic footnotes. Only complaint I’ve heard is the older style of English is more difficult to understand.